I've done quite a bit of research on parallel 4link set ups. I know the bottom bar should be level with the road at ride height and both bars should be the same length. I also know that the way it looks now, is the way it's done to drag race. I'm don't plan to race anyone. This looks odd to me. Can anyone tell if something is wrong? It's just tack welded and would like some input before I move forward with this. Thanks.
Looks right for the setup you have shown. There is a difference between a Parallel 4 Bar setup and a 4 Link setup which is what you have shown.
You'll need a Panhard bar, and.......... well, a frame to weld it all to would be nice. As far as right, I was taught (the hard way mind you) that your bottom bars should be parallel to the marching surface (ground) and you adjust the top bars to control roll at launch, dive at brake, and pinion angle.
I'm pretty sure drag racing four links have two different radius arch (bracket hole arch) on each link. Meaning the upper link has it's own radius and the lower link a different radius. Depending on the length of link you decide to use. The bracket you used here is a typical upper link bracket used on dirt late models and modifieds. We've used these same brackets for swing arm, brake floater, 4- link, three link. I think as you move your rear end up and down you will eventually have a bind.....
.....I think as you move your rear end up and down you will eventually have a bind.....[/QUOTE] Why would there be a bind? And how is that problem solved? I have the top tab leaning forward a little bit, I thought that would give it plenty of clearance. Travel on the axle will be 5 to 6 inches, max.
I'll bet GM and Ford wish they knew that the upper bars have to be the same length as the lower bars, since I have never seen them build one that way.
Try this link. it will help you understand it more... Also your rod ends should be set in the middle so you can adjust the pinon angle.It will change when you switch holes.You can loosen the nuts and turn the bar to adjust the pinon angle if they are set in the middle without having to take them off the car every time.Also you should check your rod ends every month to make sure the look good.You don't want one to fail as your driving... Steve http://www.raceglides.com.au/files/fourlink-ladderbar-tips.pdf
Some of those bars have right and left hand threads that allow you to adjust them without taking them loose you just have to loosen the jam nut.
Correct on the lower bar being parallel to the ground. The upper bar is used for fine tuning the pinion angle, anti dive and launch of the rear end. I haven't found a 4 link setup that wont have a bind some where. Binding is from 2 separate bars at 2 different heights moving in an different arch fashions. Heims versus poly bushings are a big part as well. I have gone as far as to build my link setups utilizing both the heims and poly bushings to keep a great ride with out taking away of the snappy reaction of a great launch or leave at a stop light.
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